Blade center lock



March 15, 1960 H. A. AUSTIN ETAL 2,928,587

BLADE CENTER LOCK Filed April 12, 1957 IN V EN TOR.

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BLADE CENTER LOCK Application April 12, 1957, Serial No. 652,611

Claims. (Cl. 230-134) This invention relates to centrifugal blower wheels and, more particularly, it relates to an improved structure for locking the central portions of the blades of such a blower wheel to a center plate structure.

It is a problem of major importance in blower wheel constructions, to provide an effective means for locking the central portions of the blades to a center plate structure so as to prevent radial and circumferential movement of the blades, or the rims secured thereto, with respect to the center plate structure. A variety of different constructions have been devised for accomplishing this purpose but, in general, such structures have been undesirable for one or another of a variety of reasons. For example, certain types of blade center locks have not been satisfactory because they did not give a sufliciently rigid connection of the blades to the center plate structure and this resulted in the blades becoming loose and wobbly during use of the Wheel. Other constructions, while providing a satisfactory blade center lock, have been undesirable because they employ a structure which is complicated and/or expensive to manufacture.

. Accordingly, it is a major object of this invention to provide an improved center plate and blade construction for a blower wheel, particularly, an improved blade center lock structure for such a wheel.

It is a further object of this invention to provide an improved blade lock construction, as aforesaid, in which the longitudinally central portions of the blades will be firmly held against relative radial and circumferential movement with respect to the center plate structure of the wheel.

' It is a further object of this invention to provide an.

improved blade lock construction, as aforesaid, which is economical to manufacture and which provides a rigid.

and durable blower wheel structure.

' Other objects and advantages of this invention will become apparent to those acquainted with equipment ofthis type upon reading the following description and in-' spection of the accompanying drawings, in which:

Figure 1 is a front elevational partially broken view of a blower wheel and housing therefor, taken from the outlet side of the housing;

Figure 2 is an exploded view of a fragment of Figure 1, illustrating the improved blade lock construction to which this invention relates;

' Figure 3 is a fragmentary view similar to Figure 2 showing the blade lock construction prior to complete assembly;

Figure 4 is a sectional view taken alongthe line IV- IV of Figure 2. 1

This invention provides a blower wheel having a plurality of circumferentially spaced blades, each of said blades having structure defining a pair of spaced ears extending in opposite, axial directions adjacent the radially inner edge of the blade. A pair of radially extending center plates are positioned within the wheel and are provided with a series of circumferentially spaced open States tent O each of the blades is received within one of the openings inone of the center plates, and the other car on'each of the blades is received-within an opening in the other of the center plates.

Detailed description Referring to the drawings, there is shown in Figure l a centrifugal blower wheel construction, including a. housing 10 and a blower wheel 11 within said housing The housing may be of any conventional construction" and is here provided with inlets 12 and 13 at the re spective axial ends thereof and with an outlet 14. The housing 10 is supported on a pair of legs 16 and 17.

The blower wheel 11 includes a plurality of circumferentially spaced blades 18, which blades may be of any desired configuration and curvature. The blades 18 are secured as desired at their respective axial ends to end ring structures 19 and 21, which structures may be of any suitable, conventional type. The wheel 11 is mounted for rotation on a shaft 22, which shaft may be mounted in bearings and rotated by any suitable power source, such as an electric motor (not shown).

Referring to Figures 2, 3 and 4, the blades 18 are each provided with a notch 23 in' the radially inner edge thereof, which notch is in this embodiment located midway between the axial ends of the blades. The notch is formed to provide a T-shaped member 24 integral with the blades 18, which member extends radially inwardly and is of the same curvature, if any, as the blades. The T-shaped member 24 includes a pair of cars 26 and 27,

; which extend toward the respective axial ends of the blades. Preferably, the shank portion 28 of the T-shaped member 24 is relatively thick for strength purposes.

The center plate structure 29 of the blower wheel 11 includes a pair of circular plates 31 and 32. The plates, 31 and 32 have radially outer portions 33 and 34, respectively, which portions are substantially parallel with each other and, after assembly, are spaced axially a distance less than the axial distance between the ends of the ears 26 and 27. The outer edge of each of the'radially outer portions 33 and 34 is preferably provided with a series of circumferentially spaced recesses 36 which are adapted to engage the radially outer edge 37 of the notch 23. The recesses 36 provide for locating the blades 18 in predetermined, circumferentially spaced relationship during the wheel assembly operation but are not essential for all purposes of the invention. The portions 33 and 34 have a series of circumferentially spaced openings 38 and 39, respectively, therethrough, said openings being located radially inwardly with respect to the recesses 36. The cars 26 and 27 of the T-shaped member 24 are received through the openings 38 and 39 in the portions 33 and iiig's adjacent the radial outer edge thereof. One car on 5 34, respectively. The openings 38 and 39 are aligned with the recesses 36 so that when a blade is properly seated in said recesses, the cars 26 and 27 thereof will be aligned with said openings. The ears 26 and 27 are'preferably tapered away from the shank 28 and the openings 38 and 39 preferably have a diameter slightly less than the maximum width of their corresponding ears. Thus,. when the ears 26 and 27 are received into the openings 38 and 39, respectively, and the plates 31 and 32 are urged toward each other, said ears will be firmlywedged,

in contact with the walls defining said openings and will be thereby held firmly against either radial or c'ircumfe'b: ential movement with respect .to said center structure 29.. In orderto maintain the holding of the blades 18 by the center structure 29, it is essential that the center plates 31'- and 32 be secured to each other. This may be iace 'm plished by any suitable means, such as welding or rivet-" ing. When so held, the peripheral edges ofthe plates 31f. and 32 will be sprung away from each'other asshow n in} the drawings. Such springing of'said plates '31'aud32" 3- V will hold said plates tightly and continuously against said ears, and thereby prevent eventual loosening 'of the blades. The radially inner portions of the. plates 31 and.32 diverge with respect to each other and are secured at their radially inner ends to the shaft 22 in any suitable manner. In: the disclosed embodiment of the invention, the plate 32 is secured to a hub 43, which hub is secured to the shaft22 by a set screw 44; Similar structure may be provided forplate 31. t

In assembly, the blades .18 and plates 31 and 32 will be assembled while-held in a suitable fixture which may be of the type shown in the co-pending application Serial No. 652,493, filed April 12, 1957, entitled fFixture for Assembling Blower Wheels, and assigned to the assignee of this application. The plates 31 and 32 will be received into the notches 23 andsecured to the blades by moving said plates from a position adjacent the axial endsof the cars 26 and 27 toward each other, so that the openings 38 and 39 receive the ears 26 and 27"as statedi above. The portions 33 and 34 of the plates 31 and 32 H are then secured together as above described, and the centerplates are secured tothe shaft thereafter. The end rings Hand 21 may be secured to the respective axial ends of the blades 18 in any suitable manner, such as described in detail in the. co-pending applicationSerial No. 652,525, filed April 12, 1957,fentitled Apparatus and Method for Assembling aCentrifugal Blower Whee and assigned to the assignee of this application.

The blades 18 may be of any desired construction, in-

eluding circumferentially curved blades, as shown in;Fig.

4, so long as the ears 26 and 27 are provided thereon.

The blades may be formed by any suitable type of form- ,ing operation, such as by stamping. Similarly, the center plates 31 and 32 may have a variety of configurations, depending upon specific design requirements, so long as they are provided with the parallel, radially outer portions 33 and 34 which receive the cars 26 and 27 of the 'T -shaped member 24, as above described. The center plates 31 and 32 may be formed in .any desired fashion,

radially outer portions of said plates being received within said notchon either axial side of said T-shaped member andbeing spaced apart a distance less than the distance between the axial ends of said ears, said radially outer portions having a series of circumferentially spaced holes therethrough, said holes corresponding'in number, and

spacing to said blades, one ear of each of said T-shaped members extending through one of said holes in one of said plates and the other car of each of said T-shaped members extending through a corresponding hole in the other of said plates; and means securing said plates in fixed position with respect to each other. f

2. A centrifugal blower wheel construction, including: a plurality. of circumfcrentially spaced, axially elongated blades having inner radial edges parallel with the axis of the wheel, eachof said' blades being circumferentially curved having cut-out portions defining, a notch therein between the axial ends thereof, saidrnotch extending outwardly from the radially inner edge of said blade; said. cut ou-t' portions defining a T-shaped member within said notch and extending inwardly fromthe outer edge there of, said T-shaped member being integral with, and being of the same. curvature as, said blade, the ears of said T-shaped member being adjacent the radially inneredge of said' blade and extending, respectively, toward the opposite axial ends of said blade; a pair of similar, radially extending centerplates substantially parallelwith each other, the radially outer portions of, said plates being received within said notch on either axial, side of said T-shaped member and being spaced apart a distance less than the distance between the axial ends of said ears, said radially outer portions having a series of circumferential ly spaced holes therethrough, said holes corresponding in number and spacing to said blades, one ear.of each of said T-shaped members extending through one of said holes in one of'said plates and the other ear of each of said T-shaped members extending through a correspond:

' ing hole in thei other of said plate; a series of circumfersuch as by stamping. However, the outer portions 33 and 34 must be capable of being bent or flared, as appearing in Figure 2, during the final assembly of the center structure 29. a e

The blower wheel construction of the present invention providesa stable and rigid blower wheel, in which the ,entially spaced recesses in the radially outer ,edge of said 7 plates, each of said recesses receiving the radially outer edge of the notch ,of one of said blades; said plates having planar portions in contact with, and secured to,

' each otherradially inwardly of said blades.

central portions. of the blades areefiectively locked against radial or circumferential movement during' normal operation of the wheel. Thus, the blades 18, the rings 19 and 21 secured'thereto, and the center structure 29, become one rigid unit.

The foregoing description has, for convenience, referred to the center plate structure as being, located midway between the axial ends of the blades. It will be apparent that the center plate structure maygwithin the scope of this invention, be ofiset axially from the center of the blades. V

Although a particular, preferred embodiment of the invention'has been disclosed herein for illustrative purposes, it will be understood that variations or modifica-' tions thereof, which 'lie within the scope of such invention, are fully contemplated, unless specifically stated to the contrary in the hereinafter appended claims.

We claim:

' 1.. A centrifugal blower wheel construction, including: aplurality of circumferentially spaced, axially elongated blades having inner radial edges parallel -with the axis of the wheel, each of said bladeshaving a notch therein between the axial ends. thereof,said notch extending outwardly from the radially inner edge of said blade; a T-shaped member within said notch and extending inwardly therein, the ears of said T-shaped member being adjacent the radial inner edge of said blade and extend-' ing, respectively, toward' the opposite axial ends of said blade; a pair of radially extending center plates, the

3. A centrifugal blower wheel construction, including: a plurality of circumferentially spaced, axially elongated blades with axially, extendingradially inner edges, each of said blades having an inwardly extending T-shaped member adjacent the radially inner edge thereof, the ears of said T-shaped member extending, respectively, toward. the opposite axial ends of said blade; a pair of. center plates having radially. outermost portions diverging with respect to each other in a radially outer direction, said radially outermost portions of said plates being spacedfrom each other a distance less than the distance between the axial ends'of said ears, said radially outer-' most portions of said plates having a series of circumferentially spaced holes therethrough, said holes corresponding in number and spacing to said blades, one ear of each of said T-shaped members extending through a hole in one of said plates 'andthe other ear of each of said withinsaid notch and extending, inwardly from the outer edgethereof, the ears of said T'-shaped member being adjacent the inner edg'elot' said blade and extending, respectively, toward the. opposite axiali ends of, said blade,

converging outer edges defining cam surfaces; a pair of,

similar radially extending center plates, said plates having radially outermost portions diverging with respect to each other in a radially outer direction, said radially outermost portions of said plates being received within said notch on either axial side of said T-shaped member and being spaced apart a distance less than the distance between the axial ends of said ears, said radially outermost portions having a series of circumferentially spaced holes therethrough, said holes corresponding in number and spacing to said blades, one ear of each of said T-shaped members extending through a hole in one of said plates and the other car of said T-shaped members extending through a corresponding hole in the other of said plates, said cam surfaces contacting the edges of,

said holes; said plates having planar, contiguous portions secured to each other radially inwardly of said blades.

5. A centrifugal blower wheel construction, comprising: a plurality of circumferentially spaced, axially elongated blades with axially extending, radially inner edges, each blade being curved around an axis parallel with said inner edge; means fixed with respect to each blade defining a pair of adjacent ears spaced from, and

extending toward, the opposite axial ends of said blade, said ears being positioned radially outwardly of said radially inner edge; and a pair of center plates secured with respect to each other and having radially outer portions spaced from each other a distance less than the distance between the axial ends of said ears, said outer portions of said plates having a plurality of circumferentially spaced, axially aligned openings into which said ears are respectively received.

References Cited in the file of this patent UNITED STATES PATENTS 770,207 Wilkinson Sept. 13, 1904 1,325,208 Rice Dec. 16, 1919 2,415,033 Nygren Jan. 28, 1947 2,637,489 Place May 5, 1953 2,745,171 King et al. May 15, 1956 2,772,851 Stalker Dec. 4, 1956 FOREIGN PATENTS 375,169 Great Britain June 23,1932

492,801 Great Britain Sept. 27, 1938 Great Britain Dec. 13, 1938 

